Add offset plane point-and-click user flow (#4552)

* Add a code mod for offset plane

* Add support for default plane selections to our `otherSelections` object

* Make availableVars work without a selection range
(because default planes don't have one)

* Make default planes selectable in cmdbar even if AST is empty

* Add offset plane command and activate in toolbar

* Avoid unnecessary error when sketching on offset plane by returning early

* Add supporting test features for offset plane E2E test

* Add WIP E2E test for offset plane
Struggling to get local electron test suite running properly

* Typos

* Lints

* Fix test by making it a web-based one:
I couldn't use the cmdBar fixture with an electron test for some reason.

* Update src/lib/commandBarConfigs/modelingCommandConfig.ts

* Update src/machines/modelingMachine.ts

* Revert changes to `homePageFixture`, as they were unused

* @Irev-Dev feedback: convert action to actor, fix machine layout

* Update plane icon to be not dashed, follow conventions closer

src/lib/commandBarConfigs/modelingCommandConfig.ts

@@ -40,6 +40,10 @@ export type ModelingCommandSchema = {
     selection: Selections
     radius: KclCommandValue
   }
+  'Offset plane': {
+    plane: Selections
+    distance: KclCommandValue
+  }
   'change tool': {
     tool: SketchTool
   }
@@ -276,6 +280,24 @@ export const modelingMachineCommandConfig: StateMachineCommandSetConfig<
       },
     },
   },
+  'Offset plane': {
+    description: 'Offset a plane.',
+    icon: 'plane',
+    args: {
+      plane: {
+        inputType: 'selection',
+        selectionTypes: ['plane'],
+        multiple: false,
+        required: true,
+        skip: true,
+      },
+      distance: {
+        inputType: 'kcl',
+        defaultValue: KCL_DEFAULT_LENGTH,
+        required: true,
+      },
+    },
+  },
   Fillet: {
     description: 'Fillet edge',
     icon: 'fillet',